<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Jquery</title>
</head>
    <script src="../../js/jquery-1.4.2.js"></script>
<body>

</body>
    <script>
        jQuery(function (){
            alert("JQuery引入成功了")
        })

        $(function (){
            alert("jQuery引入成功了")
        })

        $(document).ready(function () {
            alert("JQuery引入成功")
        })
    </script>
</html>